The need to communicate data is an endemic need of modern society. Data is communicated by way of a communication system. And, a communication system includes, at least a set of communication stations and a communication channel that interconnects the communication stations. Data is originated at, or otherwise sourced, at a first of the communication stations, and the data is caused to be communicated upon the communication channel to another communication station of the set of communication stations. The communication station from which the data is sent is referred to as a sending station, and the communication station to which the data is communicated is referred to as a receiving station. Data is communicated to effectuate many varied types of communication services. And, different types of communication systems have been developed by which to provide for the effectuation of the different types of communication services. As advancements in communication technologies permit, communication systems are developed and implemented that permit effectuation of new types of data services or data services of improved capabilities and qualities. Advancements in communication technologies, for instance, have permitted the introduction of new types of radio communication systems as well as improvements to the capabilities and performance of existing communication systems.
In a radio communication system, the communication channels upon which data is communicated between sending and receiving stations are defined upon a radio air interface extending therebetween. Wire line connections, conventionally required in a conventional wire line communication system to interconnect the sending and receiving stations is not required. Installation and use of a radio communication system provides various advantages over a wire line counterpart. Costs associated with the initial installation and deployment of a radio communication system are generally less than the corresponding costs required to install and deploy a wire line counterpart. Additionally, a radio communication system is amenable for implementation as a mobile communication system in which communication mobility is provided.
A type of radio communication system that is widely deployed and popularly utilized is a cellular communication system. Network infrastructures of cellular communication systems have been installed to encompass many of the populated areas of the world. Usage of cellular communication systems to communicate therethrough is increasing, both in terms of increased numbers of users and increased amounts of usage.
Initial deployments of cellular communication systems made use of analog communication techniques, utilizing circuit switched connections. Circuit switched voice communications as well as low bandwidth data communication services are effectuable in such first deployed cellular communication systems.
Successive generations of cellular communication systems have been developed, installed, and deployed. Successor generation systems generally utilize digital communication techniques and provide for packet switched communications in which packet formatted data is communicated pursuant to effectuation of communication services.
Ongoing standardization procedures related to an operating specification of a universal mobile telephone service/general packet radio service (UMTS/GPRS) also pertain to a radio communication system that provides for packet switched communication services.
Other radio communication systems provide communication services analogous to those provided by cellular communication systems. And, corresponding advancements in communication technologies have been implemented in such systems, or have made such systems possible. For instance, WLANs (Wireless Local Area Networks) provide for radio communications with users of mobile stations. WLANs have been implemented both as private network systems and public network systems. WLANs generally provide for the effectuation of high data rate communication services, sometimes at costs substantially lower than the effectuation of corresponding communication services in a public access cellular communication system.
WLANs are sometimes implemented to be operable in compliance with the operating protocol set forth in an IEEE 802.11, or variant, operating specification. WLANs of this type of implementation provides for high bandwidth communication services, e.g., between 11 and 54 Mbps within relatively small coverage areas.
WLANs provide complementary communication services to those provided by wide area cellular communication systems. Communication sessions are formable between a mobile station operable in a WLAN and a communication station operable in an external network when the external network and the WLAN are appropriately connected theretogether. The external network forms, for instance, a UMTS/GPRS system. A mobile station operable in the UMTS/GPRS operates, for instance, to initiate to a mobile station operable in the WLAN. The call forms, for instance, an IMS call. Pursuant to call initiation, the UMTS/GPRS mobile station sends an SIP (Session Initiation Protocol) INVITE to a SIP server of the UMTS network. The radio portion of the UMTS network is sometimes referred to as an UTRAN (UMTS Terrestrial Radio Access Network). A call session control function (CSCF) is embodied at the server. The CSCF determines that the terminating station is beyond the domain of the UMTS and forwards the INVITE message to a SIP server in the WLAN. And, the SIP server of the WLAN forwards the message to the terminating mobile station. A problem occurs in the event that the terminating mobile station is not in an active mode when the INVITE message is broadcast thereto. Namely, if the mobile station is in a dormant mode when the message is broadcast, the mobile station does not detect the message, and a negative reply is returned to the UMTS.
While proposals have been set by which to multicast the INVITE message over a wide area, such as multicasting the message within a sub network and hierarchically through an entire domain, the problems associated with non detection of the message at a dormant mobile station are not adequately solved.
If a manner could be provided by which better to alert a dormant mobile station of the call initiation, improved communication operations would be possible.
It is in light of this background information related to initiation of a communication session in a radio communication system that the significant improvements of the present invention have evolved.